Affordable Irrigation Controller Project Proposal ECE 445. Jae Choi Nicholas Foss Andrew Xu. TA: Katherine O Kane

Transcription

1 Affordable Irrigation Controller Project Proposal ECE 445 Choi Nicholas Foss Xu TA: Katherine O Kane

2 Table of Contents 1.0 Introduction 1.1 Statement of Purpose 1.2 Objectives Goals Functions Benefits Features 2.0 Design 2.1 Block Diagram 2.2 Block Description Power Module Water Control Data Collection Water Source 3.0 Requirements and Verification 3.1 Table of Requirements and Verification 3.2 Tolerance Analysis 4.0 Cost and Schedule 4.1 Cost Analysis Labor Parts Grand Total 4.2 Schedule 1

3 1.0 Introduction 1.1 Statement of Purpose Crop production is critical to the survivability of most farmers in a developing country. Most need to produce a specific yield just to feed their families, and the surplus sold to market acts as their income. In Honduras for example, water can be hard to come by, and it is crucial that this valuable resource is used in an intelligent way so that the farmer may feed his/her family and receive some income for his/her work. That s where we come into play. Our goal is to create an affordable and self-sustaining irrigation controller that intelligently waters these crops. Today, smart irrigation systems do exist, but they are expensive and require electricity, internet, and other resources that are not available to most in a developing nation. Our device will provide the developing world with a tool that increase the chance of a successful harvest at a low resource cost. 1.2 Objectives Goals Create a self-sustaining, low resource-cost irrigation controller that will increase crop yields Functions Based on weather and soil data, waters crops intelligently to increase crop yields Uses water in an intelligent manner to preserve this scarce resource as much as possible Benefits Preserves water more-so than traditional manual watering since environmental characteristics are measured directly (i.e., only watering when necessary) Saves the farmer time since the entire system is automated Features Self-sustaining Does not require other resources such as electricity or WiFi to function 2

4 2.0 Design 2.1 Block Diagram 2.2 Block Description Power Module The power module will be our main power management unit. It consists of two rechargeable NiMH battery packs of different voltages - 4.8v and 9v. Each battery is recharged by a solar panel. This module directly powers the water control unit as well powering the irrigation valve in the water source unit when our microcontroller decides it is time to water Water Control The water control unit will be the brains of our controller. It holds an arduino microcontroller and connects to all 3 other modules. It receives power from our power module via a 5v battery, which is the correct operational voltage for this specific microcontroller. The arduino will receive data from data collection, run our own algorithm on the data, and finally decide whether it is appropriate to drive a transistor to allow the irrigation valve in the water source module to open up, thus watering the crops. 3

5 2.2.2 Data Collection The data collection module will be responsible for providing the arduino in water control important environmental data. This will be accomplished via sensors including soil moisture, humidity, temperature, and barometric pressure Water Source The water source module is the part of our system that physically waters the crops when instructed to do so. The 9v battery from the power module is connected to a transistor that acts as a switch. When the water control module decides it is an appropriate time to water, the arduino drives the transistor to allow current to flow through it, thus causing the solenoid valve to open up. 4

6 3.0 Requirements and Verification 3.1 Table of Requirements and Verification Requirements Verification Points 1a. Power Supply - Solar Panels Output voltage is +/- 10% of expected Panels should provide enough charge to the batteries for semi-continuous operation 1b. Power Supply - Battery Packs Provide 4.8V +/-.5 and 8.4V +/-.5. Must also be rechargeable 2a. Data Collection - Moisture Correctly return changes in soil moisture 2b. Data Collection - Barometer Readings must be within 10% accuracy of true values 2c. Data Collection - Temperature and Humidity Readings must be within 10% accuracy of true values 3. Water Control - Arduino Uno Able to function with at least 4.3V Take the panels outside on a sunny day and measure voltage using a multimeter. Filter sunlight to simulate cloudier days Set up a circuit to simulate power draw of the system (powered with the rechargeable batteries), place the circuit outside in sunlight, and let the circuit run for half an hour - the first half with panels exposed to sun and second half with panels covered Drain batteries of power, charge them with voltage roughly 50% higher than battery voltage, and check voltages with multimeter Put the sensor in soil, slowly add moisture into soil and observe changes in sensor reading Take values read from barometer and compare to known working barometer. If possible, change pressure and check again Take values read from temperature/humidity sensor and compare to true values. Vary their surroundings with a warm and moist towel, then compare again Power the Uno with 4.3V and upload simple code that will verify a transistor can be activated with the Uno output. We can use an external LED connected in series with the transistor to do this Water Source - Solenoid Solenoid should open with 6V Provide 6V source to the solenoid and see if it opens 15 5

7 3.2 Tolerance Analysis Since the system is meant to be self sustaining, the power supply is the most vital and volatile part of the project. Due to the large variations in weather, there is a chance that the system may go days with little to no sunlight. In these scenarios the system should not only stay powered, but maintain an acceptable voltage (4.8v +/-.5v to power the Arduino Uno microprocessor, and 8.4v +/-.5v to drive the solenoid valve when necessary) as well since other components may not perform properly if voltage drops too low. Consequently, the power management of the microprocessor comes close second in importance, since we do not want it to consume too much power and drain our battery below our tolerance range of 4.8v +/-.5v, i.e., use power efficiently so that the battery will remain consistently charged enough to not fall below proper tolerance levels. 6

8 4.0 Cost and Schedule 4.1 Cost Analysis Labor 75 ($/hr) * 250 (hrs) * 3 (persons) = $ Parts Brass Liquid Solenoid Valve - 12V - $25 Arduino Uno - $20 4.8V Rechargeable Battery Pack - $20 8.4V Rechargeable Battery Pack - $22 Soil Moisture Sensor - $5 Humidity and Temperature Sensor - $10 Barometric Pressure Sensor - $5 Solar Panel 7.7V - $50 Solar Panel 15.4V - $70 Parts Total = $ Grand Total $

9 4.2 Schedule WEEK TASK RESPONSIBLE Write proposal 14-Sep Write proposal Write proposal Finalize parts list & order 21-Sep Finalize parts list & order Finalize parts list & order Test parts (power) 28-Sep Test parts (sensors) Test parts (solenoid + MP) Assemble power unit 5-Oct Assemble sensors array Write MP code Modify power unit 12-Oct Modify sensors array Modify MP code Test prototype 19-Oct Test prototype Test prototype 26-Oct 2-Nov Get PCB printed 9-Nov Get PCB printed Get PCB printed Final assembly 16-Nov Final assembly Final assembly Break 23-Nov Break Break Write final paper 30-Nov Make final powerpoint Prep demo and more Wrap up and revise 7-Dec Wrap up and revise Wrap up and revise 8